docs: def _transitionerFromInstance(oself, symbol, automaton):
      """
      Get a L{Transitioner}
      """
      transitioner = getattr(oself, symbol, None)
      if transitioner is None:
          transitioner = Transitioner(
              automaton,
              automaton.initialState,
          )
          setattr(oself, symbol, transitioner)
      return transitioner